Articulated mats are used for offshore coastal and marine applications where separation, stabilization, protection, and impact prevention is needed for pipelines and other underwater installations. These mats are particularly useful in areas where considerable hydrodynamic forces are generated by bottom currents and waves. For example, a seabed pipeline can be covered with such a mat so that the pipeline is stabilized by the weight of the mat and protected from impact. Another benefit of the mat is its ability to prevent erosion of the adjoining seabed. Examples of articulated mats, their components, and their uses are given in European patent specification 0152232, and U.S. Pat. Nos. 2,876,628; 2,674,856; 4,370,075; 4,357,928; 4,417,828; 5,052,859; and 5,193,937.
The most effective soil covering is concrete because of its high tensile and compressive strength and its almost endless resistance to the action of natural types of water. Concrete mats alone can scratch pipelines and underwater structures. The scratching of the epoxy coating is detrimental to the pipeline or metallic structure because the epoxy provides protection from external environmental conditions that cause the pipeline to corrode. Prior art mats required a tunnel with an insulating material as shown in U.S. Pat. No. 5,193,937 to prevent abrasion and unwanted thermal conduction. Others use solid antiabrasion mats which do not permit cathodic protection of the metallic structure. Additionally, prior art mats have traditionally be unable to be easily linked to one another after installation.
There is, therefore, a need in the art for an articulated seabed mat that can be easily landed on the seabed, particularly in deep waters, and linked to other mats. There is also a continuing need in the art for improved subsea mats that additionally do not scratch or ablate the protective epoxy coating of underwater pipelines and other underwater installations.